The immediate goal is the production of electrocardiographic body surface maps from infants and children for whom correlative hemodynamic (cardiac catheterization) data are available. A total of 156 electrodes will be used. The entire array will be scanned in .5 msec, and maps will be generated at 1 msec intervals. Surface maps will be normalized to eliminate both the shape factor and the effect of the discontinuity in conductivity at the body surface. To accomplish this, several photographic and holographic techniques will be explored that can give instantaneous body geometry (necessary for the normalization procedure). Normalization for mean body conductivity will also be explored. Correlations between surface maps and hemodynamic data will be sought heuristically from direct examination of the records and by utilizing pattern recognition and biostatistical techniques.